Abstract

In the title compound, [Fe(C5H5)(C23H21N2S2)], the cyclo­penta­dienyl rings of the ferrocenyl unit deviate slightly from the eclipsed form. In the pyrazoline ring, the N atom bonded to S-benzyl dithio­carbazate exhibits unconventional sp2-hybrid character in order to form an extended conjugated system. The pyrazoline ring displays an envelope conformation. The mol­ecules are linked into chains along the b axis via C—HS inter­molecular hydrogen bonds.

Acknowledgments

The authors thank the Natural Science Foundation of Yangzhou University (No. 2006XJJ03) for financial support of this work.

supplementary crystallographic
information

Comment

Pyrazoline derivatives are an important class of conjugated fluorescent dyes
emitting blue fluorescence and have been extensively applied in the industry
due to the high fluorescence quantum yield (Wilkinson et al., 1990;
Rivett et al., 1979). For example, pyrazolines have been widely used as
optical brightening agents for textiles, paper and fabrics and as a
hole-conveying medium in photoconductive materials (Sun et al., 2004;
Huang & Katzenellenbogen, 2000; Wiley et al., 1958). We found that
ferrocene derivatives have good properties of fluorescence and coordination
chemistry with many metal ions (Huang et al., 1998; Shi et al.,
2004). Continuing our research (Liu et al., 2007) we report the
synthesis and structure of the title compound, (I).

In the structure of (I), the substituted ring (Cps) and unsubstituted
ring (Cp) of the ferrocenyl moiety are slightly deprived from eclipsed
form, with the five pseudo-torsion angles in the range 10.5 (2) — 10.9 (3)°.
The distances from central Fe(II) ion to Cps center [Cg(1)] and to Cp
center [Cg(2)] are 1.651 (3) Å and 1.656 (2) Å, respectively. The
angle Cg(1)–Fe–Cg(2) is 177.9 (3)° and the central Fe(II) ion
is located almost in the middle of the two cyclopentadiene rings which are not
parallel because their dihedral angle is 2.3 (4)° (Fig. 1).

In the pyrazolinyl ring, the C=N and C–N bond lengths are in agreement with
those found in similar structures (Fahrni et al., 2003). However, the
N–N bond length is longer than those found in the above-cited structures. But
the bond distance of C21–N1 is shorter than a C–N single bond and slight
longer than a C=N double bond. It might contribute to unclassical
sp2-hybrid N1 atom which is evident from the sum of the three angles
around the N1 atom being 360° (Table 1) and that atoms C21, N1, N2 and C13
are co-planar. Furthemore, atoms S2, C21, N1, N2, C13 along with adjacent
phenyl ring result in a large cojugated system.

Experimental

The title compound was synthesized by refluxing an absolute ethanol solution of
1-(4-methylphenyl)-3-ferrocenylprop-2-en-1-one (3.30 g, 10 mmol) and
S-benzyldithiocarbazate (1.98 g, 10 mmol) for 24 h. After refrigeration
(278 K) of the solution for 10 h, yellow pricipite separated out and
recrystallized from a mixture of 1,2-dichloroethane and petroleum ether (5:1
volume ratio) (3.1 g, yield 61%). The yellow crystals suitable for X-ray
analysis were obtained by slow evaporation of a dichloromethane solution at
278 K.

Refinement

All H atoms were fixed geometrically at ideal positions and allowed to ride on
the parent atoms with C—H distances 0.96, 0.97, 0.98 and 0.93 Å for CH3,
CH2, CH and aromatic CH groups, respectively, and with Uiso(H)
values of 1.2 and 1.5 times Ueq(C) for the nonmethyl and methyl
groups, respectively.

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger.